The present invention relates to forming electrical contacts and junctions in silicon carbide. More specifically, but without limitation thereto, the present invention relates to incorporating dopants in silicon carbide from a gaseous ambient and concurrently activating the dopants by photo illumination.
The semiconductor silicon carbide (SiC) enjoys wide interest due to its applicability in high temperature, high power and photonic devices and circuits. However, greater difficulties in fabrication relative to silicon have prevented the full realization of its capabilities in these applications. The high melting point and limited diffusion of impurities in silicon carbide have greatly limited the use of ion implantation and furnace annealing commonly employed in the silicon microelectronics industry as a means of incorporating and activating dopants. These fabrication techniques are desirable for producing self-aligned field-effect transistor structures for use in discrete power devices and digital logic circuits. Ion implantation of n-type dopants, such as arsenic, in SiC has met with limited success; however, it requires annealing temperatures in excess of 1300.degree. C. for activation, and ion implantation and annealing of p-type dopants has demonstrated only about 5% activation, insufficient for practical device fabrication. Alternative techniques are therefore desired to obtain a greater degree of dopant activation in SiC, particularly with p-type dopants.